At their best politicians can be hugely entertaining. All, though some more consciously than others, are by nature performers. They can affect anger, indignation and sensitivity at will. Inevitably, however, their repertoire changes over the centuries. Until 1850 or so, politicians occasionally fought each other in a duel. Death was uncommonly the result, but a delighted public could often count on a serious wound or two. William Pitt took on George Tierney, while Charles James Fox was wounded by William Adam. In the latter contest, Fox jokingly remarked that he would certainly have been killed but for the fact that his opponent had been using government powder.

The duel in question in this book was fought in 1809 between Lord Castlereagh and George Canning. Both were members of the Duke of Portland's Cabinet. One was Secretary of State for War and the other was Secretary of State for Foreign Affairs. Since each of them should have been directing all his efforts towards the destruction of Napoleon Bonaparte, their attempts to kill each other were relished. It suggested that their priorities had become somewhat blurred. Both men had gallons of Irish blood in their veins, but some further explanation seemed necessary.

In fact, the two protagonists had a great deal in common: each had started life as an admirer of Fox; each had been 'Pittised' by the terrible consequences of the French Revolution; and each was to be numbered among the great man's disciples. Only temperament divided them. Castlereagh was reserved, serious-minded and vulnerable to any suggestion that his abilities were less than first class. Canning, on the other hand, liked to tease. He had 'a horrid vice of quizzing', and referred to George III as 'Knobbs'. He reflected that 'marriage does fine men odd turns', and warned his son against a political career lest he should 'feel, & fret, & lament, & despise, as much as his father'.

The point at issue in this duel is well set out by Giles Hunt in the most authoritative chapter of the book. The war was not going well in 1809. The army of Sir John Moore had just been forced out of Spain, and the expedition to Walcheren had ended in a fiasco. Canning was clear that Castlereagh's War Office had much to answer for, and began to agitate for his rival's dismissal. Portland agreed with this point of view, but omitted to tell Castlereagh that his prospects were not good. Not unreasonably, therefore, the latter gentleman concluded that he had been the victim of a conspiracy orchestrated by Canning, and demanded satisfaction. Canning had no choice but to comply, even though Portland was the real culprit. The two men met on Putney Heath and each fired twice. With his second shot, Castlereagh, by far the better marksman, wounded his opponent in the thigh, making 'a Rent in Mr Canning's Pantaloons'.

Much could be made of this story, but Hunt merely makes it the filling for a sandwich. The first hundred pages of the book are devoted to a review of the careers of Canning and Castlereagh up to 1809. The last forty or so are given over to their later careers. Inevitably, in such a short space, not much new is said. A more profitable approach might have been to linger on the duel itself, to give it context and tease out meaning.

For any duel was a meeting between gentlemen interested in the defence of their honour. Only gentlemen had this commodity. Other people settled their differences in court. This is a point of some consequence in this particular duel. No one had any doubt about Castlereagh's credentials: his veins ran with blue blood. But George Canning had reason to be grateful that, by being called out, his gentle status was publicly affirmed. Throughout his life, he struggled with sneers and jibes about his parentage. His father had been a ne'er-do-well, and to make a living his mother had to become an actress, presenting her clever son with two rough stepfathers and a shoal of penniless stepbrothers and sisters. In the status-conscious world of the late eighteenth century, it was an inheritance of the most doubtful kind. As a result, while being shot at by a great landowner was no fun, it had the one advantage of proclaiming to the world that, in Castlereagh's eyes, Canning was a gentleman and worth calling out.

Then, as Giles Hunt briefly notices, there was the question of public opinion. By 1809, the duel was rapidly going out of fashion, except among military men. Moralists denounced it as un-Christian; the King objected to his ministers taking such risks; and lawyers demanded punishments. Worst of all, middle-class people began to adopt the practice, even though, in the opinion of the upper orders, they had no honour to defend. As was usual in English society, when an area of privilege was invaded by the people at large, aristocrats abandoned their positions and moved elsewhere. There was no point in gentlemen duelling if it no longer made them distinctive. In choosing to fight, Castlereagh was in danger of being called old-fashioned.

The present author is not tempted to chase these hares. Instead, he has written a pleasant book about a rather bizarre episode. It might be called deckchair history to be read in the spring or summer. It gently reminds us of what politicians were once capable. It might induce a longing that modern statesmen might sometimes be tempted to take the same course.

Leslie Mitchell is Emeritus Fellow of University College, Oxford. His most recent publications include a life of Bulwer-Lytton and a study of the Whig Party entitled 'The Whig World'.